The present invention relates to an electric lawn mower including an electric motor and a rechargeable battery unit for driving the electric motor.
Known electric lawn mowers are disclosed, for example, in Japanese Patent No. 2880116 entitled xe2x80x9cPOWER HEAD ASSEMBLY FOR ELECTRIC MOWERxe2x80x9d and in Japanese Patent Laid-Open Publication No. HEI-10-257814 entitled xe2x80x9cELECTRIC LAWN MOWERxe2x80x9d.
The electric lawn mower disclosed in Japanese Patent No. 2880116 includes a lower housing having an electric motor mounted thereto. The lawn mower includes front and rear batteries having the electric motor interposed therebetween. One problem with the thus arranged lawn mower is that heat produced by the electric motor and heat produced by the batteries adversely affect or interfere with each other. That is, the electric motor and the batteries would fail to release heat therefrom.
The electric lawn mower disclosed in Japanese Patent Laid-Open Publication No. HEI-10-257814 includes a cutter housing, and an electric motor mounted to the cutter housing. Batteries of the lawn mower are disposed in the form of a V. The batteries have the electric motor disposed between front ends thereof.
The batteries are disposed rearwardly of the electric motor. With this arrangement, the weight of the electric motor would not be balanced with the weight of the batteries. The lawn mower thus arranged may be made hard to manipulate. What has been needed is an easy-to-operate electric lawn mower including a battery and an electric motor designed to release heat therefrom.
According to one aspect of the present invention, there is provided an electric lawn mower including: a cutter blade; a cutter housing for enclosing the cutter blade therein; an electric motor for rotating the cutter blade, the electric motor being mounted on the cutter housing; and at least one rechargeable battery unit for driving the electric motor, the battery unit being positioned above the electric motor.
As is well known in the art, the electric motor and the battery unit are heavier components forming the electric lawn mower. Generally, the electric motor serves to rotate the cutter blade in a horizontal plane. Thus, the electric motor is positioned substantially centrally of the cutter housing. Manipulation of the electric lawn mower is influenced by where the heavy battery unit is positioned. This is why the battery unit is disposed above the electric motor. This allows the electric lawn mower to lie stably. The electric lawn mower thus arranged can be handled well to thereby cut grass with improved efficiency. By positioning the battery unit above the cutter blade, there can be achieved weight balance of the electric lawn mower. Further, the electric motor and the battery unit allow air to flow smoothly therebetween.
Preferably, the cutter housing may have a battery bracket attached thereto. The battery bracket includes a body portion covering the sides and top of the electric motor. The battery bracket has the battery unit mounted thereto. The electric motor is spaced from the battery unit, such that heat of the electric motor and heat of the battery unit do not interfere with each other.
Further, the battery bracket and the electric motor may be secured together to the cutter housing. It thus becomes possible to assemble the electric lawn mower with improved efficiency.
Preferably, the battery bracket may be made of metal, and have air vents formed at portions thereof where the battery unit is mounted. This arrangement helps the electric motor and the battery unit release heat therefrom.
Further, the electric motor may include a rotational shaft having an axis extending through the battery unit positioned above the electric motor. This arrangement is suitable for achieving weight balance of the electric lawn mower.
Preferably, the battery unit may include at least one upper battery disposed above the electric motor and a front battery positioned in front of the electric motor. With this arrangement, the electric lawn mower can reliably provide weight balance. Such an electric lawn mower can be manipulated with improved efficiency.
Further, the cutter housing may have a battery bracket attached thereto. The battery bracket includes a body portion covering the sides and top of the electric motor, and an extension portion extending forward from the body portion. The body portion has the upper battery mounted there on whilst the extension portion has the front battery mounted thereon. The upper battery is spaced from the front battery. With this arrangement, air flows smoothly between the battery unit and the electric motor to thereby promote heat radiation from the battery unit and the electric motor.